The invention relates to an apparatus for the control of actuators by means of pneumatic pulses, especially for the control of feeders in milking stands.
In the milking stands, feed is dispensed to the cows during the milking, this feed serving as a regular feeding or as a "treat". In the first case, each cow is individually given an amount of feed corresponding to her milk output. In the second case, all animals are dispensed the same small amount of feed which is intended to entice them into their milking stations.
The proportioning of the feed can be accomplished, for example, by means of a proportioning dispenser consisting of a compartmented wheel whose compartments are advanced by a certain angular amount each time so that the compartments are emptied one by one, thus dispensing a certain amount of feed (portion) to the animals. The animals each receive a total amount of feed corresponding to the number of movements of the compartmented wheel.
The feed distributor--the compartmented wheel in this case--can be operated by hand or mechanically, or also automatically on the basis of the presetting of the desired number of portions.
In the case of automatic dispensing, a drive must be provided which operates the compartmented wheel. In addition, the number of movements (portions) must be controlled. At this point a pulse control is used, which acts on a servo mechanism or directly on the actuator, e.g., on a pneumatically powered cylinder and piston.
The known controlling means in milking installations are electrical and electronic apparatus, which are sensitive, however, to environmental conditions such as moisture and aggressive atmospheres. Furthermore, these apparatus are of complex construction, and for even simple service operations an extensive technical knowledge is necessary, which the operators of these installations do not have in most cases. Also, for each feeder a pulse drive must be installed, and each drive has to be adjusted separately for each cow. This is also the case with the known pneumatic pulsators which operate on compressed air. Since the operators of milking installations ordinarily do not have compressed air available, such pulsators are inappropriate.